Hypolipemiant besides antileukemic effect of imatinib mesylate

Identification of immune infiltration-related biomarkers in carotid atherosclerotic plaques

Atherosclerosis is a chronic lipid-driven inflammatory response of the innate and adaptive immune systems, and it is responsible for several cardiovascular ischemic events. The present study aimed to determine immune infiltration-related biomarkers in carotid atherosclerotic plaques (CAPs). Gene expression profiles of CAPs were extracted from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) between the CAPs and control groups were screened by the "limma" package in R software. Immune cell infiltration between the CAPs and control groups was evaluated by the single sample gene set enrichment analysis. Key infiltrating immune cells in the CAPs group were screened by the Wilcoxon test and least absolute shrinkage and selection operator regression. The weighted gene co-expression network analysis was used to identify immune cell-related genes. Hub genes were identified by the protein-protein interaction (PPI) network. Receiver operating characteristic curve analysis was performed to assess the gene's ability to differentiate between the CAPs and control groups. Finally, we constructed a miRNA-gene-transcription factor network of hub genes by using the ENCODE database. Eleven different types of immune infiltration-related cells were identified between the CAPs and control groups. A total of 1,586 differentially expressed immunity-related genes were obtained through intersection between DEGs and immune-related genes. Twenty hub genes were screened through the PPI network. Eventually, 7 genes (BTK, LYN, PTPN11, CD163, CD4, ITGAL, and ITGB7) were identified as the hub genes of CAPs, and these genes may serve as the estimable drug targets for patients with CAPs.

The potential effect of imatinib against hypercholesterolemia induced atherosclerosis, endothelial dysfunction and hepatic injury in rabbits

AIMS

Imatinib is an effective tyrosine kinase inhibitor which has different therapeutic actions. The recent work demonstrated the possible beneficial effects of imatinib on the progression of atherosclerosis, endothelial dysfunction, and hypercholesterolemia-associated liver damage in rabbits.

MAIN METHODS

Animals had been distributed in 4 groups: group 1 (non-treated): animals fed regular diet; group 2 high cholesterol [HC]: animals fed 1% cholesterol supplemented diet for 30 days; group 3 (HC-Imatinib): animals fed 1% cholesterol supplemented diet+imatinib (0.01 g/kg daily, p.o) for 30 days; group 4 (Imatinib): animals fed regular diet with imatinib (0.01 g/kg daily, p.o). After thirty days, tissue samples and blood were isolated to be detected biochemically, histologically, and for in vitro analysis.

KEY FINDINGS

HC exhibited significant elevations in serum lipid parameters, CRP, ALT, AST and ALP. Additionally, HC induced significant increases for aortic and hepatic MDA, aortic NO and hepatic PDGFR-β, while significantly exhibited reductions in aortic and hepatic GSH, SOD and hepatic PPARγ1. Moreover, HC produced impairment in ACh-enhanced aortic relaxation and aortic pathological changes. Histopathological examination of HC-fed rabbits revealed hepatic steatosis compared with non-treated group. Imatinib administration exhibited significant decreases in serum lipid parameters, CRP, ALT, AST and ALP. Additionally, imatinib induced significant decreases for aortic and hepatic MDA, aortic NO and hepatic PDGFR-β, while significantly exhibited elevations in aortic and hepatic GSH, SOD and hepatic PPARγ1 compared with HC animals. Furthermore, imatinib significantly protected against HC produced attenuation in ACh-induced aortic relaxation and pathological changes in aortic and hepatic tissues. Interestingly, imatinib could return serum CRP, ALP, hepatic SOD and PDGFR-β to basal values.

SIGNIFICANCE

The recent observation reports that imatinib could have beneficial effect against atherosclerosis progression, vascular malfunction, and liver damage in high cholesterol diet (HCD)-fed rabbits.

The BCR-ABL1 Inhibitors Imatinib and Ponatinib Decrease Plasma Cholesterol and Atherosclerosis, and Nilotinib and Ponatinib Activate Coagulation in a Translational Mouse Model

Treatment with the second and third generation BCR-ABL1 tyrosine kinase inhibitors (TKIs) increases cardiovascular risk in chronic myeloid leukemia (CML) patients. We investigated the vascular adverse effects of three generations of TKIs in a translational model for atherosclerosis, the APOE*3Leiden.CETP mouse. Mice were treated for sixteen weeks with imatinib (150 mg/kg BID), nilotinib (10 and 30 mg/kg QD) or ponatinib (3 and 10 mg/kg QD), giving similar drug exposures as in CML-patients. Cardiovascular risk factors were analyzed longitudinally, and histopathological analysis of atherosclerosis and transcriptome analysis of the liver was performed. Imatinib and ponatinib decreased plasma cholesterol (imatinib, −69%, p < 0.001; ponatinib 3 mg/kg, −37%, p < 0.001; ponatinib 10 mg/kg−44%, p < 0.001) and atherosclerotic lesion area (imatinib, −78%, p < 0.001; ponatinib 3 mg/kg, −52%, p = 0.002; ponatinib 10 mg/kg, −48%, p = 0.006), which were not affected by nilotinib. In addition, imatinib increased plaque stability. Gene expression and pathway analysis demonstrated that ponatinib enhanced the mRNA expression of coagulation factors of both the contact activation (intrinsic) and tissue factor (extrinsic) pathways. In line with this, ponatinib enhanced plasma levels of FVII, whereas nilotinib increased plasma FVIIa activity. While imatinib showed a beneficial cardiovascular risk profile, nilotinib and ponatinib increased the cardiovascular risk through induction of a pro-thrombotic state.

Tyrosine kinase inhibitors and mesenchymal stromal cells: effects on self-renewal, commitment and functions

The hope of selectively targeting cancer cells by therapy and eradicating definitively malignancies is based on the identification of pathways or metabolisms that clearly distinguish “normal” from “transformed” phenotypes. Some tyrosine kinase activities, specifically unregulated and potently activated in malignant cells, might represent important targets of therapy. Consequently, tyrosine kinase inhibitors (TKIs) might be thought as the “vanguard” of molecularly targeted therapy for human neoplasias. Imatinib and the successive generations of inhibitors of Bcr-Abl1 kinase, represent the major successful examples of TKI use in cancer treatment. Other tyrosine kinases have been selected as targets of therapy, but the efficacy of their inhibition, although evident, is less definite. Two major negative effects exist in this therapeutic strategy and are linked to the specificity of the drugs and to the role of the targeted kinase in non-malignant cells. In this review, we will discuss the data available on the TKIs effects on the metabolism and functions of mesenchymal stromal cells (MSCs). MSCs are widely distributed in human tissues and play key physiological roles; nevertheless, they might be responsible for important pathologies. At present, bone marrow (BM) MSCs have been studied in greater detail, for both embryological origins and functions. The available data are evocative of an unexpected degree of complexity and heterogeneity of BM-MSCs. It is conceivable that this grade of intricacy occurs also in MSCs of other organs. Therefore, in perspective, the negative effects of TKIs on MSCs might represent a critical problem in long-term cancer therapies based on such inhibitors.

BCR-ABL Tyrosine Kinase Inhibitors: Which Mechanism(s) May Explain the Risk of Thrombosis?

Imatinib, the first-in-class BCR-ABL tyrosine kinase inhibitor (TKI), had been a revolution for the treatment of chronic myeloid leukemia (CML) and had greatly enhanced patient survival. Second- (dasatinib, nilotinib, and bosutinib) and third-generation (ponatinib) TKIs have been developed to be effective against BCR-ABL mutations making imatinib less effective. However, these treatments have been associated with arterial occlusive events. This review gathers clinical data and experiments about the pathophysiology of these arterial occlusive events with BCR-ABL TKIs. Imatinib is associated with very low rates of thrombosis, suggesting a potentially protecting cardiovascular effect of this treatment in patients with BCR-ABL CML. This protective effect might be mediated by decreased platelet secretion and activation, decreased leukocyte recruitment, and anti-inflammatory or antifibrotic effects. Clinical data have guided mechanistic studies toward alteration of platelet functions and atherosclerosis development, which might be secondary to metabolism impairment. Dasatinib, nilotinib, and ponatinib affect endothelial cells and might induce atherogenesis through increased vascular permeability. Nilotinib also impairs platelet functions and induces hyperglycemia and dyslipidemia that might contribute to atherosclerosis development. Description of the pathophysiology of arterial thrombotic events is necessary to implement risk minimization strategies.

The anti-leukemic and lipid lowering effects of imatinib are not hindered by statins in CML: a retrospective clinical study and in vitro assessment of lipid-genes transcription

Imatinib, which has revolutionized chronic myeloid leukemia (CML) treatment, was suggested to improve lipid profile. Statins, a dyslipidemia drug, were reported to potentiate imatinib's antileukemic effect. However, analysis of imatinib combined with statins is lacking. We have retrospectively analyzed the normalization period of bcr-abl, blood counts, and lipids in 40 CML patients, 19 of which co-treated with statins, during short (<12 months) and prolonged (>12 months) imatinib treatment. Prior statins treatment did not hinder nor sensitized imatinib's anti-leukemic and lipid-lowering effects. CML cells (K562) treated with 1μM imatinib (24-96 h) were further assessed for the expression of central lipid-related genes by real-time PCR. HMGCoAR, LDL-R, and apobec1 expressions were significantly increased while CETP declined after 48-96 h. To conclude, imatinib produces an independent favorable lipid profile, which is not hindered by statins and is partly mediated via transcription regulation of genes involved in the clearance of plasma lipids.

European LeukemiaNet recommendations for the management and avoidance of adverse events of treatment in chronic myeloid leukaemia

Most reports on chronic myeloid leukaemia (CML) treatment with tyrosine kinase inhibitors (TKIs) focus on efficacy, particularly on molecular response and outcome. In contrast, adverse events (AEs) are often reported as infrequent, minor, tolerable and manageable, but they are increasingly important as therapy is potentially lifelong and multiple TKIs are available. For this reason, the European LeukemiaNet panel for CML management recommendations presents an exhaustive and critical summary of AEs emerging during CML treatment, to assist their understanding, management and prevention. There are five major conclusions. First, the main purpose of CML treatment is the antileukemic effect. Suboptimal management of AEs must not compromise this first objective. Second, most patients will have AEs, usually early, mostly mild to moderate, and which will resolve spontaneously or are easily controlled by simple means. Third, reduction or interruption of treatment must only be done if optimal management of the AE cannot be accomplished in other ways, and frequent monitoring is needed to detect resolution of the AE as early as possible. Fourth, attention must be given to comorbidities and drug interactions, and to new events unrelated to TKIs that are inevitable during such a prolonged treatment. Fifth, some TKI-related AEs have emerged which were not predicted or detected in earlier studies, maybe because of suboptimal attention to or absence from the preclinical data. Overall, imatinib has demonstrated a good long-term safety profile, though recent findings suggest underestimation of symptom severity by physicians. Second and third generation TKIs have shown higher response rates, but have been associated with unexpected problems, some of which could be irreversible. We hope these recommendations will help to minimise adverse events, and we believe that an optimal management of them will be rewarded by better TKI compliance and thus better CML outcomes, together with better quality of life.

PPARγ Antagonist Gleevec Improves Insulin Sensitivity and Promotes the Browning of White Adipose Tissue

Blocking phosphorylation of peroxisome proliferator-activated receptor (PPAR)γ at Ser(273) is one of the key mechanisms for antidiabetes drugs to target PPARγ. Using high-throughput phosphorylation screening, we here describe that Gleevec blocks cyclin-dependent kinase 5-mediated PPARγ phosphorylation devoid of classical agonism as a PPARγ antagonist ligand. In high fat-fed mice, Gleevec improved insulin sensitivity without causing severe side effects associated with other PPARγ-targeting drugs. Furthermore, Gleevec reduces lipogenic and gluconeogenic gene expression in liver and ameliorates inflammation in adipose tissues. Interestingly, Gleevec increases browning of white adipose tissue and energy expenditure. Taken together, the results indicate that Gleevec exhibits greater beneficial effects on both glucose/lipid metabolism and energy homeostasis by blocking PPARγ phosphorylation. These data illustrate that Gleevec could be a novel therapeutic agent for use in insulin resistance and type 2 diabetes.

Imatinib reduces cholesterol uptake and matrix metalloproteinase activity in human THP-1 macrophages

BACKGROUND

Imatinib mesylate (Glivec®, formerly STI-571) is a selective tyrosine kinase inhibitor used for the treatment of chronic myeloid leukemia and gastrointestinal stromal tumors. However, there are reports suggesting that imatinib could be atheroprotective by lowering plasma low-density lipoprotein (LDL).

AIM

To investigate the potential inhibitory effect of imatinib on cholesterol uptake in human macrophages as well as its effect on matrix metalloproteinase (MMP) activity.

METHODS AND RESULTS

Uptake of fluorescence-labeled LDL was analyzed using flow cytometry. Macrophages treated with imatinib showed a 23.5%, 27%, and 15% decrease in uptake of native LDL (p<0.05), acetylated LDL (p<0.01), and copper-modified oxidized LDL (p<0.01), respectively. Gel-based zymography showed that secretion and activity of MMP-2 and MMP-9 were inhibited by imatinib. Using GeneChip Whole Transcript Expression array analysis, no obvious gene candidates involved in the mechanisms of cholesterol metabolism or MMP regulation were found to be affected by imatinib. Instead, we found that imatinib up-regulated microRNA 155 (miR155) by 43.8% and down-regulated ADAM metallopeptidase domain 28 (ADAM28) by 41.4%. Both genes could potentially play an atheroprotective role and would be interesting targets in future studies.

CONCLUSION

Our results indicate that imatinib causes post-translational inhibition with respect to cholesterol uptake and regulation of MMP-2 and MMP-9. More research is needed to further evaluate the role of imatinib in the regulation of other genes and processes.

Peripheral artery occlusive disease in chronic phase chronic myeloid leukemia patients treated with nilotinib or imatinib

Several retrospective studies have described the clinical manifestation of peripheral artery occlusive disease (PAOD) in patients receiving nilotinib. We thus prospectively screened for PAOD in patients with chronic phase chronic myeloid leukemia (CP CML) being treated with tyrosine kinase inhibitors (TKI), including imatinib and nilotinib. One hundred and fifty-nine consecutive patients were evaluated for clinical and biochemical risk factors for cardiovascular disease. Non-invasive assessment for PAOD included determination of the ankle-brachial index (ABI) and duplex ultrasonography. A second cohort consisted of patients with clinically manifest PAOD recruited from additional collaborating centers. Pathological ABI were significantly more frequent in patients on first-line nilotinib (7 of 27; 26%) and in patients on second-line nilotinib (10 of 28; 35.7%) as compared with patients on first-line imatinib (3 of 48; 6.3%). Clinically manifest PAOD was identified in five patients, all with current or previous nilotinib exposure only. Relative risk for PAOD determined by a pathological ABI in first-line nilotinib-treated patients as compared with first-line imatinib-treated patients was 10.3. PAOD is more frequently observed in patients receiving nilotinib as compared with imatinib. Owing to the severe nature of clinically manifest PAOD, longitudinal non-invasive monitoring and careful assessment of risk factors is warranted.

Suppression of PDGF-induced PI3 kinase activity by imatinib promotes adipogenesis and adiponectin secretion

Improved glucose and lipid metabolism is a unique side effect of imatinib therapy in some chronic myeloid leukaemia (CML) patients. We recently reported that plasma levels of adiponectin, an important regulator of insulin sensitivity, are elevated following imatinib therapy in CML patients, which could account for these improved metabolic outcomes. Adiponectin is secreted exclusively from adipocytes, suggesting that imatinib modulates adiponectin levels directly, by transcriptional upregulation of adiponectin in pre-existing adipocytes, and/or indirectly, by stimulating adipogenesis. In this report, we have demonstrated that imatinib promotes adipogenic differentiation of human mesenchymal stromal cells (MSCs), which in turn secrete high-molecular-weight adiponectin. Conversely, imatinib does not stimulate adiponectin secretion from mature adipocytes. We hypothesise that inhibition of PDGFRα (PDGFRA) and PDGFRβ (PDGFRB) is the mechanism by which imatinib promotes adipogenesis. Supporting this, functional blocking antibodies to PDGFR promote adipogenesis and adiponectin secretion in MSC cultures. We have shown that imatinib is a potent inhibitor of PDGF-induced PI3 kinase activation and, using a PI3 kinase p110α-specific inhibitor (PIK-75), we have demonstrated that suppression of this pathway recapitulates the effects of imatinib on MSC differentiation. Furthermore, using mitogens that activate the PI3 kinase pathway, or MSCs expressing constitutively activated Akt, we have shown that activation of the PI3 kinase pathway negates the pro-adipogenic effects of imatinib. Taken together, our results suggest that imatinib increases plasma adiponectin levels by promoting adipogenesis through the suppression of PI3 kinase signalling downstream of PDGFR.

Plasma adiponectin levels are markedly elevated in imatinib-treated chronic myeloid leukemia (CML) patients: a mechanism for improved insulin sensitivity in type 2 diabetic CML patients?

CONTEXT

The mechanism(s) by which imatinib improves glycemic control in chronic myeloid leukemia (CML) patients with type 2 diabetes remains unclear.

OBJECTIVE

Adiponectin is an important regulator of insulin sensitivity that is secreted exclusively by adipocytes. We previously reported that imatinib promotes adipocytic differentiation of mesenchymal stromal cells. We therefore hypothesized that imatinib therapy would be associated with an increase in peripheral and intramedullary adiposity and elevated plasma adiponectin levels.

RESEARCH DESIGN AND METHODS

Adiponectin levels in CML patient plasma, at diagnosis and then during imatinib mesylate therapy, was measured using an ELISA. Adiponectin multimers in plasma were analyzed using nondenaturing PAGE and immunoblotting. Intramedullary adiposity and adipose tissue mass was determined using histomorphometry and dual-energy X-ray absorptiometry, respectively.

RESULTS

In CML patients, an increase in intramedullary and peripheral adiposity was observed after 6 months of imatinib therapy and plasma adiponectin levels, in the form of high- and low-molecular-weight complexes, were elevated 3-fold, compared with pretreatment levels, after 3, 6, and 12 months of therapy.

CONCLUSIONS

Elevated adiponectin levels in imatinib-treated CML patients provide a possible mechanism for improved glucose and lipid metabolism reported for some imatinib-treated patients.